Elasticsearch: Use _field_caps instead of _mapping to get fields (#97607)

pkg/services/featuremgmt/registry.go

@@ -1676,6 +1676,12 @@ var (
 			Owner:        grafanaOperatorExperienceSquad,
 			HideFromDocs: true,
 		},
+		{
+			Name:        "elasticsearchCrossClusterSearch",
+			Description: "Enables cross cluster search in the Elasticsearch datasource",
+			Stage:       FeatureStagePublicPreview,
+			Owner:       awsDatasourcesSquad,
+		},
 	}
 )
 

pkg/services/featuremgmt/toggles_gen.csv

@@ -223,3 +223,4 @@ alertingUIOptimizeReducer,GA,@grafana/alerting-squad,false,false,true
 azureMonitorEnableUserAuth,GA,@grafana/partner-datasources,false,false,false
 alertingNotificationsStepMode,experimental,@grafana/alerting-squad,false,false,true
 feedbackButton,experimental,@grafana/grafana-operator-experience-squad,false,false,false
+elasticsearchCrossClusterSearch,preview,@grafana/aws-datasources,false,false,false

pkg/services/featuremgmt/toggles_gen.go

@@ -902,4 +902,8 @@ const (
 	// FlagFeedbackButton
 	// Enables a button to send feedback from the Grafana UI
 	FlagFeedbackButton = "feedbackButton"
+
+	// FlagElasticsearchCrossClusterSearch
+	// Enables cross cluster search in the Elasticsearch datasource
+	FlagElasticsearchCrossClusterSearch = "elasticsearchCrossClusterSearch"
 )

pkg/services/featuremgmt/toggles_gen.json

@@ -1269,6 +1269,21 @@
         "frontend": true
       }
     },
+    {
+      "metadata": {
+        "name": "elasticsearchCrossClusterSearch",
+        "resourceVersion": "1733848475752",
+        "creationTimestamp": "2024-12-09T13:53:38Z",
+        "annotations": {
+          "grafana.app/updatedTimestamp": "2024-12-10 16:34:35.752111 +0000 UTC"
+        }
+      },
+      "spec": {
+        "description": "Enables cross cluster search in the Elasticsearch datasource",
+        "stage": "preview",
+        "codeowner": "@grafana/aws-datasources"
+      }
+    },
     {
       "metadata": {
         "name": "enableDatagridEditing",

pkg/tsdb/elasticsearch/elasticsearch.go

@@ -182,14 +182,21 @@ func (s *Service) getDSInfo(ctx context.Context, pluginCtx backend.PluginContext
 	return &instance, nil
 }
 
+func isFieldCaps(url string) bool {
+	return strings.HasSuffix(url, "/_field_caps") || url == "_field_caps"
+}
+
 func (s *Service) CallResource(ctx context.Context, req *backend.CallResourceRequest, sender backend.CallResourceResponseSender) error {
 	logger := s.logger.FromContext(ctx)
 	// allowed paths for resource calls:
 	// - empty string for fetching db version
 	// - /_mapping for fetching index mapping, e.g. requests going to `index/_mapping`
+	// - /_field_caps for fetching field capabilities, e.g. requests going to `index/_field_caps`
 	// - _msearch for executing getTerms queries
 	// - _mapping for fetching "root" index mappings
-	if req.Path != "" && !strings.HasSuffix(req.Path, "/_mapping") && req.Path != "_msearch" && req.Path != "_mapping" {
+	// - _field_caps for fetching "root" field capabilities
+	if req.Path != "" && !isFieldCaps(req.Path) && req.Path != "_msearch" &&
+		!strings.HasSuffix(req.Path, "/_mapping") && req.Path != "_mapping" {
 		logger.Error("Invalid resource path", "path", req.Path)
 		return fmt.Errorf("invalid resource URL: %s", req.Path)
 	}
@@ -266,6 +273,9 @@ func createElasticsearchURL(req *backend.CallResourceRequest, ds *es.DatasourceI
 	}
 
 	esUrl.Path = path.Join(esUrl.Path, req.Path)
+	if isFieldCaps(req.Path) {
+		esUrl.RawQuery = "fields=*"
+	}
 	esUrlString := esUrl.String()
 	// If the request path is empty and the URL does not end with a slash, add a slash to the URL.
 	// This ensures that for version checks executed to the root URL, the URL ends with a slash.